Scale the fish and cut some slices about one and a half inches thick, and wipe them perfectly dry. Allow two ounces of good butter and the strained juice of one lemon to each pound of fish and a tablespoonful of white wine. Rub the bottom of a stewpan well with the butter and lay in the fish, straining the lemon juice over it, and seasoning it with a sprinkling of salt. Lay a buttered paper over the fish, and then put the cover on the pan, and let it cook, allowing twenty minutes for each pound of fish. When the fish is cooked, dish it on a hot dish, garnish with little heaps of the cucumber garnish round it, strain the gravy from the stewpan through a tammy, mix with it a teaspoonful of finely chopped tarragon and chervil, and pour this over the fish.
Peel and cut the cucumber into one and a half inch lengths, quarter these, remove all the seeds, and cut into olive shapes. Lay them in cold water with a pinch of salt, and bring it to the boil, then skim and let the cucumber cook till tender. Then strain it from the water, stir in to it a pat of fresh butter and a few drops of strained lemon juice, sprinkle with a little chopped parsley, and use.